Porphyrias are rare types of genetic blood disorders in which patients have a defect in heme production, an important part of hemoglobin. Blisters are a sign of porphyria cutanea tarda, the most common type of porphyria.

A brain tumor is a collection of abnormal cells in the brain, which can increase pressure in the skull. Risk factors for brain tumors include age, race, family history, and exposure to chemicals and radiation.

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